ABSTRACT Stem cells interpret mechanical forces in a broad spectrum of ways that can affect their behavior and, ultimately, their ability to drive tissue regeneration. As such, an increased understanding of the mechanosensitivity of stem cells and the manner in which mechanical signaling may be used to drive stem cell regenerative potential will greatly aid in the design of rehabilitation protocols. Unfortunately, there are few in vitro or ex vivo methods currently available which allow for modeling and quantification of the direct effect of mechanical stimuli on stem cell behavior. There is a need to develop an ex vivo system capable of modeling biologically relevant mechanical loads on stem cells in order to understand the mechanistic effects of physical forces on stem cell fate and function. There is also a need to accurately assess the effects of different types of mechanical forces experienced in vivo by endogenous stem cells existing within tissues or exogenous stem cell populations transplanted for regenerative therapies. The specific aims of the AR3T Technology Development efforts are: 1. To develop and test an ex vivo system for the mechanical conditioning of stem cell microtissue constructs and 2. To validate a system of in vivo noninvasive imaging for assessing muscle stem cell responses to mechanical loading.